1. Field of the Invention
The present invention generally relates to image display apparatus and, in a preferred embodiment thereof, more particularly relates to a projector having a space-saving tower orientation, a horizontally pivotable stabilizing support foot, and spring-loaded support leg members selectively operable to pivotally adjust the elevation of a lens-supporting portion of the projector housing.
2. Description of Related Art
A variety of electrically powered image display devices are known and include, for example, computer monitors, television sets and portable projectors for creating images on surfaces remote from the display device. Because of the typical exterior configuration of a conventional portable projector, the way in which it is typically used, and the distance of the displayed image from the projector, a variety of problems, limitations and disadvantages are commonly associated with conventionally constructed portable projectors.
For example, a conventional projector is typically of a rectangular configuration in which its vertical dimension is considerably less than its horizontal width or depth. While this is a well-known, stable configuration, it causes the projector to occupy a considerable area of the horizontal support surface (often the top of a small table) upon which it is placed for use. This vertically compact configuration places the projector""s lens at a relatively low level on the table, thereby often requiring that the projector lens be elevated (by upwardly and rearwardly pivoting the projector housing) a substantial amount to cause the projected image to be properly received on the typically elevated display screen remote from the projector. Due to this need to upwardly pivot the lens to a substantial degree the lens axis is correspondingly offset a considerable degree from being perpendicular to the screen. This, in turn, often causes an undesirable xe2x80x9ckeystoningxe2x80x9d angular distortion of the projected image on the remote display screen.
Moreover, because of the low vertical profile of the conventionally configured projector, and the resulting low placement of its lens relative to the horizonal projectorxe2x80x94supporting surface, it is difficult for the projector to xe2x80x9cshoot overxe2x80x9d obstacles disposed on the support surfacexe2x80x94such as glasses, plants, etc. These items must typically be removed from the front portion of the support surface, to one side of the projector, or removed from the support surface altogether.
Additionally, the necessary pivotal elevation adjustment of the projector can be a somewhat cumbersome, awkward task. Conventionally, a front underside portion of the projector housing is provided with screw-in elevating legs. To pivotally elevate or lower the projector relative to its supporting surface, and correspondingly adjust the image location on the screen, it is typically necessary to lift a front portion of the projector while laboriously screwing its elevating legs in or out as the case may be.
As can readily be seen from the foregoing, a need exists for an improved portable projector that eliminates or at least substantially reduces the above-mentioned problems, limitations and disadvantages of conventionally constructed projectors of the type generally described above. It is to this need that the present invention is directed.
In carrying out principles of the present invention, in accordance with a preferred embodiment thereof, a specially designed image display device is provided. Representatively, the display device is a portable projector operatively connectable to a VGA port of a computer, but could alternatively be a display device of a variety of other types, including a slide projector or a computer monitor, and could be connected to a variety of other types of video input signals such as video signals from a DVD drive, a VCR, or a television,
In a preferred embodiment thereof, the projector comprises a housing supportable on a horizontal surface with a bottom side of the housing facing the horizontal surface. Preferably, the housing is of a vertically elongated tower configuration. The housing carries an image creation system operative to create a viewable image. According to one aspect of the invention, the housing carries specially designed elevation adjustment apparatus operative to engage the horizontal support surface and adjustably elevate a portion of the housing relative thereto.
From a broad perspective, the elevation adjustment apparatus includes an elevating structure vertically movable relative to the bottom housing side between downwardly extended and upwardly retracted positions in which the elevating structure respectively lifts and lowers the portion of the housing relative to the horizontal surface. A biasing structure resiliently biases the elevating structure toward its downwardly extended position, and a latch structure is operative to releasably lock the elevating structure.
Preferably, a bottom end portion of the elevating structure is defined by an elongated support foot structure operative to stabilize the vertically elongated projector. The support foot structure is horizontally pivotable relative to the balance of the elevating structure between a retracted position in which the foot structure is disposed substantially within the horizontal footprint of the housing, and an extended position in which opposite ends of the support foot project outwardly from the bottom side of the housing, beyond opposite sides thereof, and stabilize the tower configured projector against side-to-side tipping.
Illustratively, the elevating structure is incorporated in a specially designed elevator assembly operatively secured to a bottom front corner portion of the housing. The elevator assembly includes a vertically elongated pair of arcuate elevating legs which are vertically retractable into the housing interior, along opposite vertical side walls thereof and are complementarily and slidably carried in vertically elongated arcuate guide members for movement through arcuate paths. Spring structures downwardly bias the leg members toward extended positions, and the leg members have vertically spaced series of teeth thereon.
A frame member is carried within the housing for movement relative thereto transversely to the leg members and supports toothed locking members. The frame member is resiliently biased toward a position in which the teeth on the locking members engage the teeth on the elevating legs to lock them in a selectively variable vertical position relative to the housing. An opening is formed in a vertical wall of the housing and provides access to a portion of the frame member in a manner permitting it to be pushed away from its biased position to unlock the elevating legs and permit them to be resiliently driven downwardly away from their retracted positions to easily increase the operating elevation of the computer.
In a preferred embodiment of the elevator assembly, the bottom ends of the elevating legs are anchored to diametrically opposite peripheral portions of a disc member to which the support foot structure is pivotally secured. Cooperating detent structures on the foot structure and the disc member permit the foot structure to be releasably locked in either of its retracted and extended positions.